Pneumatic vibrators



May 13, 1958 L. PER-TROLLE B. BoNDEsoN ETAL 2,834,584

PNEUMATIC VIBRATORS Filed July 6, 1954 United tates Patent PNEUMATICVIBRATORS Lennart Per-Trolle Bonde Bondeson, Ljunghy, Sweden,

and Eric Fridh, Sao Paulo, Brazil, assignors to Vibro- Plus Corp.,Woodside, N. Y., a corporation of Delaware Application `nly 6, 1954,Serial No. 441,542

2 Claims. (Cl. 259-1) The present invention has for its object toeliminaten the difficulties above referred to in connection withpneumatically operated vibrators of the kind stated.

For the object stated, according to the present invention, in a vibratorof the relevant type the roller body is provided with vanes or the liketo be acted on by the airstream and so arranged that, primarily, theairstream will cause rotation of the roller body about its own axis andthereby, secondarily, cause the roller body to roll along the circularroller track.

In order to explain the invention and facilitate its carrying intoeffect, two embodiments thereof will now be described by way of examplein conjunction with the accompanying drawing illustrating apneumatically operated vibrator according to the present invention, andin which:

Fig. l is a cross-sectional view of the first embodiment of thevibrator.

Fig. 2 is a similar cross-sectional view of the second embodiment of thevibrator.

Fig. 3 is a longitudinal section through the vibrator of Fig. 2.

The vibrator of Fig. 1 comprises a casing 1 of substantially cylindricalshape and provided with substantially tangentally extending air inletopenings 2 to the interior of the casing. The air admitted is suitablydischarged from the interior of the casing 1 through outlet openings(not shown) in the end walls of the casing. Centrally disposed in thecasing and extending the full length thereof is a lixed shaft 3 whichsupports a tubular roller body 4, the inner diameter of which issubstantially greater than the diameter of the shaft 3. The roller body4 is provided on its periphery with a circumferential series of vaneorblade-like projections 5,

whereby the air under pressure admitted into the casing 1 through theinlet openings 2 will, primarily, impart to the roller body 4 a rotarymovement about its own axis. This, secondarily, will cause the rollerbody to roll along the circular roller track formed by the fixed shaft3, and the ratio of the inner diameter of the tubular roller body 4 tothe diameter of the shaft 3 will determine primarily the actualrelationship between the speed of the rotary movement of the roller body4 about its own axis and the frequency of the vibrations generated. Thisenables the operating frequency of the vibrator for any given rotationalspeed of the roller body 4` about its own axis, to be predetermined in amanner known per se by a corresponding choice of the said diametricalrice ratio, and thus it will be possible, even if the velocity of theair passed through the vibrator be kept comparatively low, to obtain avery high frequency of the vibratory movement generated. The rate of air'flow through the vibrator may, of course, be controlled by means of'asuitable throttle valve, and thus practically any desired vibratoryeffect is obtainable. It would, of course, be possible to replace theshaft 3 by a couple of trunnions projecting into and supporting theroller body 4.

Referring now to Figs. 2 and 3 of the drawing, the embodimentillustrated therein again comprises acasing 10 having interior wallsforming a cylindrical chamber. The casing has end Walls 11 withcentrally disposedopenings 12 therein in order to allow air underpressure to pass through the casing 10 in the longitudinal directionthereof. Within the casing 10 a tubular roller body 13 is disposedhaving secured within its bore a partition 14 extending helically thefull length of the roller body 13 and serving as an operating vane forthe latter. The external diameter of the roller body 13 is substantiallyless than the internal diameter of the casing 10, and v latter afterhaving blown longitudinally therethrough.`

When passing in thisway, the air under pressure will act on theoperating vane 14 whereby, upon its passage through the assembly 10, 13;the airflow will impart rotational movement to the roller body 13 aboutits own axis, and this will cause the roller body, secondarily, toperform a rolling or revolving movement in engagement with the insidewall surface ofthe casing 10. Here again the vibration frequency of thevibrator will be determined as to its order of magnitude by the ratio ofthe external diameter of the roller body to the internal diameter of thecasing, in a manner known per se, so that it will be possible, bysuitably dimensioning these diameters, to cover a wide range of desiredoperating frequencies. In addition it will be possible, ofcourse, in amanner similar to that described hereinbefore,l to varythe operatingfrequency by controlling the air flow through the vibrator casing 10 androller body 13.

It is to be understood that the invention is` not restricted to theembodiments described hereinbefore in conjunction with the accompanyingdrawing, since the same is susceptible of several variations andmodifications by anyone skilled in the art after having gained knowledgeof the inventive concept. Thus the only essential feature of theinvention resides in the facts, that, as a primary movement, the rollerbody is to berotated about its own axis by a flow of air under pressure,and that, secondarily, the said rotational movement is to be transformedinto a rolling movement or revolution of the roller body, whichpresupposes the friction between the roller track surface or race andthe roller body to be high.

What we claim is:

1. A pneumatically operated vibrator, comprising in combination, acasing having interior walls forming a cylindrical chamber provided withend walls, said end walls having substantially centrally disposedopenings therein to allow the admittance of air to one end of thechamber and the escape of the air from the other end thereof, thuscausing a ow of air in the longitudinal direction of the chamber, atubular roller body having an external diameter smaller than theinterior diameter of the chamber within the casing extending the fulllength thereof, said roller body having secured within itsi bore apartition extending helically the full length thereof, the bore of theroller body being of such Width as to cover said openings in the endwalls of the casing in any location of the roller body `within thecasing, said partition being adapted to be acted upon by the air andserving as an operating vane of the roller body, whereby, primarily,rotational movement about its own axis is limparted to the roller =bodyand, secondarily, a rolling movement in engagement 'with the inside-wall surface of the casing is imparted to the roller body.

2. A pneumatica'l-ly operated vibrator comprising means forming acylindrical chamber, a hollow tubular rolier body inthe chamber havingan external diameter Vsmaller thanzthe interior diameter of the chamber,Vmeans -to Vdirect -a `tiow Vof pressurized air longitudinally through`the hollow tubular roller Vbody and said ycylindrical chamber, and`vane means in the hollow tubular roller body responsive to the air flowto rotate the roller body whereby, primarily, rotational movement aboutits own axis is imparted to the roller body and, secendarily, -a rollingmovement in engagement with the inside wall surface of the cylindricalchamber is imparted to the roller body.

References Cited in the file of this patent UNITED STATES 'PATENTS1,346,221 Liedtke July 13, 1920 2,480,603 Peterson Aug. 30, 19492,675,777 Lachaise Apr. 20, 1954 FOREIGN PATENTS 1,056,152 France of1953 1,110,727 France Oct. 19, 1955

